What you need to do depends on your setup.
When you add force, you need to detect the direction and multiply the force with -1 for a dodge to the left. You should not disable the collider, as then your character falls through the ground. Instead tell the HP FSM that it cannot take damage during the dodge state.
How, again, depends on how you implemented it. Could be as simple as deactivating the HP FSM for a simple controller, or more involved for a more complex one.
Last, I would not use a box collider on the character in 2d to begin with, unless your levels are totally grid based and there are no slopes, ever. Rather, use a capsule collider, or a circle (freeze the z axis on the rigidbody).